The invention relates to an apparatus for automatically examining or checking an external appearance of an object such as a contact welded to a leaf spring employed in relays, switches or the like in respect of the size, position, presence of failure or the like items.
The items in respect to which the object such as the contact is to be checked may include presence of foreign matter adhering to the surface, whether such foreign matter projects outwardly remarkably from the side of the contact, whether the contact has a sufficient contacting area to attain a good electrical contact when closed, whether the deviation of the relative position of contacts to be closed is in an allowable tolerance range, and so forth. When the contact is formed with a continuous injury of a predetermined length or deposited with an adhesive foreign substance of a predetermined size, then the contact is to be excluded as fault. The same will apply to the contact deposited with welding dusts adhering to the periphery thereof or one which has undergone a welding deformation which would deteriorate the electrical insulation when the contact is opened.
The examination of the object such as the contact in respect of many items has been heretofore carried out through visual observation. However, since the object to be dealt with has a miniature size, unsatisfactory contacts are often overlooked particularly when a large number of contacts or the like objects are to be checked, which involves of course a degraded reliability of the passed object in the operation or performance thereof.